ReadPropertySet policy
The ReadPropertySet policy reads property sets and populates flow variable with the results.
This policy is aStandard policy and can be deployed to any environment type. For information on policy types and availability with each environment type, seePolicy types.
<ReadPropertySet> element
Defines a ReadPropertySet policy.
| Default Value | SeeDefault Policy tab, below |
| Required? | Required |
| Type | Complex object |
| Parent Element | N/A |
| Child Elements | <Read> |
The<ReadPropertySet> element uses the following syntax:
Syntax
The<ReadPropertySet> element uses the following syntax:
<ReadPropertySetname="read-property-set"><Read><Nameref="set-ref">property-set-name</Name><Keyref="key-ref">key-name</Key><AssignTo>var1</AssignTo><DefaultValue>default-value</DefaultValue></Read>...<IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables></ReadPropertySet>
Default Policy
The following example shows the default settings when you add a ReadPropertySet policy to your flow in the Apigee UI:
<ReadPropertySetname="read-property-set"><Read><Nameref="set-ref">property-set-name</Name><Keyref="key-ref">key-name</Key><AssignTo>var1</AssignTo><DefaultValue>default-value</DefaultValue></Read><IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables></ReadPropertySet>
When you insert a new ReadPropertySet policy in the Apigee UI, the template contains stubs for all possible operations. See below for information on required elements.
This element has the following attributes that are common to all policies:
| Attribute | Default | Required? | Description |
|---|---|---|---|
name | N/A | Required | The internal name of the policy. The value of the Optionally, use the |
continueOnError | false | Optional | Set tofalse to return an error when a policy fails. This is expected behavior for most policies. Set totrue to have flow execution continue even after a policy fails. See also: |
enabled | true | Optional | Set totrue to enforce the policy. Set tofalse toturn off the policy. The policy will not be enforced even if it remains attached to a flow. |
async | false | Deprecated | This attribute is deprecated. |
The following table provides a high level description of the child elements of<ReadPropertySet>:
| Child Element | Required? | Description |
|---|---|---|
<Read> | Required | Reads and resolves a property set variable and sets it to a specified flow variable. |
<IgnoreUnresolvedVariables> | Optional | Determines whether processing stops when a property set is unresolved. |
Example
This section provides an example using<ReadPropertySet>.
Example
This example uses<ReadPropertySet> to getpropertyset.environment.name.request.headers.api-version and assign it totarget_url. If the property set value isn't obtained,https://httpbin.org/get is used instead.
<ReadPropertySet name="read-property-set"> <Read> <Name ref="set-ref">environment.name</Name> <Key ref="key-ref">request.headers.api-version</Key> <AssignTo>target_url</AssignTo> <DefaultValue>https://httpbin.org/get</DefaultValue> </Read> <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables></ReadPropertySet>
Child element reference
This section describes the child elements of<ReadPropertySet>.
<Read>
Resolves a property set variable and sets the result in a flow variable.
The<Read> element specifes the property set variable to resolve and the flow variable to set that value to. It also includes an optional default value, which is used in the event of an unresolved property set. You can include multiple<Read> elements in a single<ReadPropertySet> policy.
| Default Value | N/A |
| Required? | Optional |
| Type | Complex type |
| Parent Element | <ReadPropertySet> |
| Child Elements | <Name><Key><AssignTo><DefaultValue> |
The<Read> element uses the following syntax:
Syntax
<Read><Nameref="set-ref">property-set-name</Name><Keyref="key-ref">key-name</Key><AssignTo>var1</AssignTo><DefaultValue>default-value</DefaultValue></Read>
Example
This example uses<ReadPropertySet> to getpropertyset.environment.name.request.headers.api-version and assign it totarget_url. If the property set value isn't obtained,https://httpbin.org/get is used instead.
<ReadPropertySet name="read-property-set"> <Read> <Name ref="environment.name">my-property-set-name</Name> <Key ref="request.headers.api-version">my-property-set-key</Key> <AssignTo>target_url</AssignTo> <DefaultValue>https://httpbin.org/get</DefaultValue> </Read> <IgnoreUnresolvedVariables>false</IgnoreUnresolvedVariables></ReadPropertySet>
The following table provides a high-level description of the child elements of<Read>.
| Child Element | Required? | Description |
|---|---|---|
<Name> | Required | String The property set to read from. Provide the ref, value, or both.Apigee first tries to resolve the
|
<Key> | Required | String The key of the property set that is used when resolving the variable. Provide the ref, value, or both.Apigee first tries to resolve the
|
<AssignTo> | Required | String Specifies the flow variable to assign the resolved variable to. |
<DefaultValue> | Optional | String Specifies a default value to use when the variable cannot be resolved. |
<IgnoreUnresolvedVariables>
Determines whether processing stops when a property set is unresolved. Set totrue to ignore unresolved variables and continue processing.
IgnoreUnresolvedVariables is not applicable when<DefaultValue> is provided.
| Default Value | False |
| Required? | Optional |
| Type | Boolean |
| Parent Element | <ReadPropertySet> |
| Child Elements | None |
Error reference
This section describes the fault codes and error messages that are returned and fault variables that are set by Apigee specific to the<ReadPropertySet> policy. This information is important to know if you are developing fault rules to handle faults. To learn more, seeWhat you need to know about policy errors andHandling faults.
Runtime errors
These errors can occur when the policy executes.
| Fault code | HTTP status | Cause |
|---|---|---|
steps.readpropertyset.UnresolvedVariable | 500 | This error occurs if a variable specified in the ReadPropertySet policy is either:
If |
Deployment errors
These errors can occur when you deploy a proxy containing this policy.
| Error name | Cause |
|---|---|
steps.readpropertyset.EmptyReads | The policy has no<Read> child elements. |
steps.readpropertyset.FieldUnset | This code is returned when any of these are true:
|
Fault variables
These variables are set when this policy triggers an error at runtime. For more information, seeWhat you need to know about policy errors.
| Variables | Where | Example |
|---|---|---|
fault.name="FAULT_NAME" | FAULT_NAME is the name of the fault, as listed in theRuntime errors table above. The fault name is the last part of the fault code. | fault.name Matches "UnresolvedVariable" |
readpropertyset.POLICY_NAME.failed | POLICY_NAME is the user-specified name of the policy that threw the fault. | readpropertyset.RPS-SetResponse.failed = true |
Example error response
Note: For error handling, the best practice is to trap theerrorcode part of the error response. Do not rely on the text in thefaultstring, because it could change.{"fault":{"faultstring":"ReadPropertySet[RPS-SetResponse]: unable to resolve variable [variable_name]","detail":{"errorcode":"steps.readpropertyset.UnresolvedVariable"}}}
Example fault rule
<FaultRule name="ReadPropertySet Faults"> <Step> <Name>RPS-CustomSetVariableErrorResponse</Name> <Condition>(fault.name = "SetVariableFailed")</Condition> </Step> <Condition>(readpropertyset.failed = true)</Condition> </FaultRule>
Schemas
Each policy type is defined by an XML schema (.xsd). For reference,policy schemas are available on GitHub.
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Last updated 2025-12-17 UTC.